Question

układy równań a){3x-y=2 {x-y=1 b) [2y-6x=-4 [3y-5x=-6 c)[x=3y+0 [x-y=15 Prosze o zrobienie

Answer 1

a) 3x - y=2

x-y=1

 

x=1+y

3(1+y) - y = 2

 

x=1+y

3+3y-y=2

 

x=1+y

2y=-1

 

x=1+y

y= -1/2

 

x=1+(-1/2) = 1/2

y=-1/2

 

b) 2y-6x=-4

3y-5x=-6

2y=-4+6x

3y-5x=-6

y=-2+3x

3(-2+3x) - 5x = -6

y=-2+3x

-6 + 9x - 5x = -6

y=-2+3x

4x = - 12

y=-2+3x

x=-3

y=-2+3 * (-3) = -11

x=-3

c) x=3y+0

3y+0 -y=15

x=3y+0

2y = 15

x=3y+0

y=7,5

x=3* 7,5+0 = 22,5

y=7,5

Answer 2

a)

{3x-y=2

{x-y=1   /*(-3)

 

{3x-y=2

{-3x+3y=-3

_________

      2y=-1  /:2

       y=-1/2

x-(-1/2)=1

x+1/2=1

x=1-1/2

x=1/2

b)

[2y-6x=-4   /*3

[3y-5x=-6   /*(-2)

 

[6y-18x=-12

[-6y+10x=12

_____________

      -8x=0   /:(-8)

         x=0

2y-6*0=-4

2y=-4   /:2

y=-2

c)

[x=3y+0

[x-y=15

 

[x-3y=0

[x-y=15   /*(-1)

 

[x-3y=0

[-x+y=-15

____________

    -2y=-15   /:(-2)

       y=7,5

x-7,5=15

x=15+7,5

x=22,5